1. Field of the Invention
This invention relates to TTL light metering devices for producing exposure value of an image by using the light passed through the objective lens, and more particularly to a weighted light metering device capable of selecting a desired region of meter sensitivity of the image format of obtaining a proper meter sensitivity distribution.
2. Description of the Prior Art
In the past, light metering devices for determining exposure values of an image format using the light passed through the objective lens, have achieved their objects by suitably changing the light metering region on the image format and meter sensitivity distribution. Light metering devices having suitable variable sensitivity distributions, have been proposed, for example, in U.S. Pat. Nos. 3,575,095 and 3,612,703 and Japanese Utility Model Application No. Sho 53-42114.
Already known in the art are a wide variety of devices for selectively controlling the meter sensitivity distribution with light entering the objective lens. The conventional methods of changing the meter sensitivity distribution, however, generally necessitate the use of two or more light metering optical systems in combination with mechanical or electrical changeover means. They therefore have the drawback that great expense is involved in using a corresponding number of pairs of a lens system and a photosensitive element. The light metering electrical circuit is also complicated. Another drawback is that the meter sensitivity distribution caused by the low degree of design flexibility of the geometrical arrangement to read the image format with a heavy weighting not right on a desired portion thereof, and free control of the meter sensitivity distribution cannot be permitted.